The title compound [Tc(S,CNEt,),N] has been prepared by the reduction of [NH,] [TcO,] with hydrazine followed by reaction with Na [S,CNEt,].The crystal structure of [Tc(S,CNEt,),N] has been determined by single-crystal X-ray diffraction methods a t 17 "C. Crystals are monoclinic, space group P2,/c, with a = 14.823(1), b = 9.1 59(1), c = 12.865(1) A, p = 107.98(1)', and Z = 4. Diffractometry has provided significant Bragg intensities for 2 152 independent reflections and the structure has been refined by full-matrix least-squares methods to R 0.042. The compound, which is isostructural with the rhenium analogue, consists of discrete [Tc(S,CNEt,),N] molecules, each containing a terminal N3-group. The technetium atom has a distorted square-pyramidal environment with the nitrogen atom in the apical position and four subhur atoms forming the base. The T E N bond, which has not been observed before, has a length of 1.604 (6) A, and G. M. Sheldrick, SHELX 76 Program for Crystal Structure Determination, Cambridge, 1976. lo W. P. Griffith, Coord. Chern. Rev., 1972, 8, 369.

The e.s.r. spectra of [TcNCI,] -and [TcNBr,] -are typical of ions with a 4d1 electronic configuration and the unpaired electron in an orbital with substantial 4dx, character. The crystal structure of [AsPh,] [TcNCI,] has been determined by single-crystal X-ray diffraction methods at 21 "C. Crystals are tetragonal, space group P4/n, with a = 12.707(2), c = 7.793(1) A, and 2 = 2. Full-matrix least-squares refinement gave a final R value of 0.031 for 1 079 independent reflections. The compound is isostructural with the series [AsPh,][MNCI,] * Supplementary data available (No. SUP 56030, 4 pp.

15 100-75-1; d-Phe-l-Phe, 2577-22-2; ~i-[(en),Co(l-Phe-I-Phe-OCH~)]~~, 99603-02-8; ~i-[(en)~Co(d-Phe-l-Phe-OCH~)]~*, 99603-03-9; A-[ (en),C~(l-Phe-l-Phe-OCH,)]~~, 99603-53-9; A-[ (en),Co(d-Phe-l-Phe-OCH3)ISt, 99559-65-6. (1 5) Bcnianszky, M. The TcV'NC1.,-anion is shown to be a useful intermediate for the preparation of T e N complexes. Reaction of AsPh,[TcNCI,] with LiBr in acetone gives AsPh4[TcNBr4], and reaction of TcNCI, with CsCl gives Cs2[TcNC15]. The TcNCIC anion undergoes reduction on reaction with PPh3, KNCS, Na[S2CNEt2], and 8-quinolinethiol (C9H6NSH) to give the TcV=N complexes [TcNCI2(PPh3),], [NEt,],[TcN(NCS),(CH,CN)], [TcN(S2CNEt2),], and [TcN(C9H6NS),], respectively. A single-crystal X-ray structure determination of bis(8-quimolinethiolato)nitridotechnetium(V), [TcN(C,H,NS),], is reported. Crystals are monoclinic, space group C2/c, with a = 15.92 (1) A, 6 = 7.347 (6) A, c = 15.33 (2) A, j3 = 110.89 (8)", and 2 = 4. Full-matrix least-squares refinement gave R = 0.029 for 1618 independent reflections. The coordination geometry of technetium is distorted square pyramidal with the apical TFN bond of length 1.623 (4) A. Tc-S and Tc-N(quinoline) bond distances are 2.3559 (7) and 2.135 (2) A, respectively.

Nitridotechnetic (VI) acid has been prepared by the hydrolysis of Cs2TcNCl5. Dissolution of this compound in concentrated HF gave an e.s.r. spectrum due to [TcNF4: g 1.895, g 1.990, A 0.03765 cm-1, A 0.01795 cm-1, Q 0.00052 cm-1 for Tcvi ; a, 0.0052 cm-l, ay 0.0010 cm-l, az , < 0.0002 cm-1 due to F-. A comparison of the 4dxy MO coefficient, β2, with those for [TcNCI4]- and [TcNBr4]-indicates that the Tc =N bond length is greater in [TcNF4]- than in [TcNCI4]- and [TcNBr4]-.

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